Theoretical Analysis of Neutron and X-ray Scattering Data on 3He |
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Authors: | E Krotscheck M Panholzer |
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Affiliation: | 1. Institut f??r Theoretische Physik, Johannes Kepler Universit?t, 4040, Linz, Austria 2. Department of Physics, University at Buffalo SUNY, Buffalo, NY, 14260, USA
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Abstract: | X-ray scattering experiments on bulk liquid 3He (Albergamo et al. in Phys. Rev. Lett. 99:205301, 2007; Schmets and Montfrooij in Phys. Rev. Lett. 100:239601, 2008; Albergamo et?al. in Phys. Rev. Lett. 100:239602, 2008) have indicated the possibility of the existence of a sharp collective mode at large momentum transfers. We address this issue within a manifestly microscopic theory of excitations in a Fermi fluid that can be understood as proper generalization of the time-honored theory of Jackson, Feenberg, and Campbell (Jackson in Phys. Rev. A 8:1529, 1973; Feenberg in Theory of Quantum Fluids, 1969; Chang and Campbell in Phys. Rev. B 13:3779, 1976) of excitations in 4He. We show that both neutron and X-ray data can be well explained within a theory where the high momentum excitations lie in fact inside the particle-hole continuum. ??Pair fluctuations?? contribute a sharpening of the mode compared to the random phase approximation (RPA). When the theoretical results are convoluted with the experimental resolution, the agreement between theory and X-ray data is quite good. |
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